High speed apparatus for line-printing



June 8, 1965 TOKU HOJO ETAL HIGH SPEED APPARATUS FOR LINE-PRINTING 3 Sheets-Sheet 1 Filed June 18, 1963 llleanm TA K' Y4 June 8, 1965 TOKU HOJO ETAL 3,187,667

HIGH SPEED APPARATUS FOR LINE-PRINTING Filed June 18, 1963 3 Sheets-Sheet 2 (n T531 M @113 @iiiiiw l @QQIIEQI @QEPIIILQ 'm 'E' $111M] June 8, 1965 TOKU HOJO ETAL HIGH SPEED APPARATUS FOR LINE-PRINTING 3 Sheets-Sheet 5 Filed June 18, 1963 Fig. 4

HIQQFaMI TAKE Yfl BY Q2 Q7 6 Arne/11E United States Patent O 3,187,667 I-HGH SPEED APPARATUS 150R LINE-PRR+IT1NG Tolrn H030 and Hirofumi Takeya, Yokohama, Japan, assignors to Hitachi, Ltd, Tokyo, Japan, a corporation of Japan Filed lune 18, 1963, Ser. No. 288,715 Claims priority, application Japan, June 20, 1962, 37/25,112 6 Claims. (Cl. 101-93) This invention relates to methods of and apparatus for line printing and particularly to those for line-printing the output information of an electronic computer or the like device.

A line-printing system serving the same purpose has previously been proposed which employs a cylinder or an endless be'lt rotating at a predetermined speed and carrying printing types arranged on its surface and a plurality of selective printing heads arranged in closely spaced opposite relation to said cylinder with a recording medium in sheet form arranged to pass through the 7 space between the cylinder and the printing heads at a constant speed. In operation, the printing types. and the recording sheet are continuously driven at constant speeds to line-print the information. To obtain satisfactory results, the arrangement and the travelling speed of the printing types, the travelling speed of the recording sheet, the arrangement of the printing heads and the time interval between the successive selecting operations are critical and must be determined so as to satisfy a number of numerical relationships. If the arrangement and dimensions of the printing types, their travelling speed, the travelling speed of the recording sheet and/or the time interval between the successive selecting operations be inaccurate or be disturbed even slightly in use, the conditions for satisfactory line-printing would no longer be satisfied resulting in misalignment of characters in each line of print. Such misalignment would be serious particularly where the kinds of characters to be printed are numerous. Under these circumstances, it has been necessary to manufacture the printing types in highly accurate dimensions and their arrangement must be strictly uniform and precise. In addition, the clock pulse signal used for controlling the selecting operation has been required to accurately conform with the travelling speed of the types as well as of the recording sheet. Thus, the proposed line-printing system has involved an additional deficiency that it needs a constant-frequency power supply and a synchronous motor or else a complicated automatic control system for proper operation of its drive mechanism. V

In order to overcome these deficiencies, the present invention provides'an improved method of and apparatus for line-printing which employs as a clock pulse or synchronizing pulse signal for selecting operation a'pulse signal obtainable by the scanning of a specialized pattern such as arranged on the surface of a rotary cylinder or disc directly connected with a rotary type-carrying cylinder with a pickup head such as a photoelectric or magnetic head or anelectric brush means, which is movable relative to the specialized pattern to Vary the pulse interval of the synchronizing pulse signal with required accuracy. p

The present invention also provides an apparatus for line-printing which is arranged so as to perform the inventive method with efficiency.

The present invention will now be described in detail with reference to the accompanying drawings, which illustrate one embodiment of the invention and in which: FIG. 1 is a schematic diagram of an apparatus em- 3,187,6 5? Patented June 8, 1365 bodying the invention and adapted for electrostatic line printing; a

FIG. 2 is a diagrammatic development of the type-'' carrying electrode of the apparatus showing the arrangement and dimensions of the types;

FIG. 3 is a plan view of the array of stationary selector electrodes showing the arrangement and dimensions thereof; and

FIG. 4 is a diagrammatic development of the synchronizing pulse generating pattern showing its arrangement and dimensions.

The apparatus shown is basicallyan electrostatic lineprinting apparatus of the previously proposed system which-is modified according to the present invention.

In FIG. 1, reference numeral 1 designates a cylindrical type-carrying electrode formed of electroconductive material and adapted to rotate in the direction indicated by the arrow under the drive of a drive source of conventional construction as known in the prior art (not shown). The rotary electrode 1 carries on its peripheral surface a number of sets of relief types 2, each set including in kinds of relief types 2 arranged in m rows andn columns, as shown in the development of FIG. 2, each row including n types of the same character. A row of n stationary selector electrodes 3 is arranged in closely spaced relation'to the rotary electrode 1. The arrangement and dimensions of the selector electrodes are illustrated in FIG. 3. A synchronizing pattern cylinder 4 is directly connected with the type-carrying electrode 1 by means of a shaft 6 and is formed on its peripheral surface with a number of synchronizing patterns or blackand-white patterns 5 for producing synchronizing pulses. Starting patterns 5 are arranged on the pattern cylinder 4 on one side of the respective synchronizing patterns 5. A pickup head including a light source 7 and a photoelectric transducer element 8' is mounted on a bar 9 fixed in spaced parallel relation to the pattern cylinder 4 for sliding movement axially thereof and can be clamped in any desired axial position. The transducer element 8 produces a printing synchronizing pulse signal 13 when it receives the light flux 7' emitted by the light source '7 and modulated by the synchronizing patterns 5. Another pickup head is provided which includes a light source 10 and a photoelectric transducer element 11 which produces a printing start signal 14 upon reception of the light flux 10 emitted by the light source 10 and modulated by the start synchronizing pattern 5'. Reference numeral 12 designates a selection controlling high voltage pulse generatingunit constructed according to the known electronic techniques. The high voltage pulse generating unit 12 is operable to supply a high voltage printing pulse 16 to any desired stationary selector electrode 3 at a desired moment upon reception of an information signal 15 from a device such as an electronic computer not shown in coincidence with the synchronizing and start signals 13 and 14. An electrostatically charged recording sheet 17 is driven by a conventional drive source not shown to pass through the space between.

the'rota ry electrode 1 and the stationary selector-electrodes 3 in the direction of the arrow. a

The cylindrical type-carrying electrode 1 and the synchronizing pulse cylinder or pattern cylinder 4, both forming an important feature ofthe present invention, will next be described in further detail. 7

As shown in FIG. 2 and as described briefly hereinbefore, the rotary electrode 1 carries on its peripheral surface a number of sets of relief character types 2. Each of the types 2 is formed of electroconductive material and included in an'area having circumferential and axial dimensions a b. The types in each set A A are arranged in m rows and n. columns, each row including n same characters. The rows and columns of the types are arranged at pitches of p and q, respectively, and the sets of types are arranged circumferentially' in a pitch of l, as illustrated.

Such arrangement of types on the rotary electrode 1 is apparently similar to that employed in the previous system but has an important difference therefrom in two points. Firstly, with the rotary electrode 1 of the present apparatus, the values of the line pitch p and the 'pitch 1 sets of types 2 thereon is extremely easy since no trouble occurs even if the types be made somewhat incorrect or their arrangement or dimensions be disturbed in use.

Referring next to FIG. 4, which illustrates the periphery of the synchronizing pulse cylinder 4 in development, reference numeral 5 indicates light-reflecting surfaces forming the synchronizing pattern for producing a. printing synchronizing pulse signal 13 having a finely adjustable pulse interval 2. The light-reflecting surfaces have each a width W and are arranged in a pitch varying from a value 17 along a circumferential line 'X 'to a value p along another circumferential line X so as to' give a predetermined range of pitch variation, C=p p Reference numeral 5' indicates light-reflecting surfaces having a width W for producing a printing start signal 14. 'As illustrated, one synchronizing pattern including in light-reflecting surfaces 5 and one starting pattern including a single light-reflecting surface '5' cooperate to form one set of patterns having a circumferential length of I The number of setsof patterns arranged circumferentially on the pattern cylinder corresponds to that of sets of types 2 arranged on the rotary electrode 1. Each of the, light-reflecting surfaces 5 and 5' preferably takes the form of a polished mirro surface of aluminum having a high light reflectivity. The remaining portions of the peripheral surface of the pattern cylindenshown hatched in FIG. 4, are treated so as to be fully absorp tive; for example, they are etched by a photoengraving process and then coatedwith a nonglossy black paint. As apparent from FIGS. 1 and 4, the pulse interval t of the, synchronizing pulse signal 13 increases from its mean value as the pickup head 7-8 is moved from the where In these formulae, p represents the pitch of the rows of types 2;V the linear speed of the types 2; v the travelling speed of the recording sheet 17; t the pulse interval of a the synchronizing pulse signal 13; p the vertical orlongitudinal dimension of the selector electrodes 3; a the length of circumferential dimension of the types 2; m the number of kinds of the characters; L the pitch of the printed lines; I the length or circumferential pitch of the sets of types; and C is the ratio V/ v, of the type speed to 4 the speed of the recording sheet 17.

with no blank space.

The first and second conditions must hold also with the case of the previous line printing system described hereinbefore in order that the line-printing may be performed in lines each including perfect aligned characters In practice, however, the condition (1) has often not been satisfied, for example, because of some inaccuracy in the pitch p of types 2 occurring in the process of their manufacture or because of some slight disturbance in the speed v of the recording sheet 17 at which it is fed by feed roller means, and thus misalignment of printed characters has resulted. Assuming that the pitch p has an inaccuracy of trip and m 64, the largest possible misalignment of the printed characters would amount to i(m1) Ap. If Ap=0.05 mm, the

' resulting misalignment would be as large as $3.15 mm.,

central circumferential line X toward the left circum with each other even with a more or less inaccuracy in V a the arrangement or dimensions of the printing types 2 which inveitably occurs in their manufacture or with some disturbance in the travelling speed of the recording sheet in use. The reason for this will be described below.

The necessary conditions for the satisfactory operation of the present system are as follows:

(A) Condition for characters to be printed in-perf ect alignment:

, (B) Condition for printing without missing any character:

P p '(C) Pitch conditionfor printedlines:

- values V, v, and t.

making the printed record practically useless. In'order to satisfy the condition 1) for obtaining printed lines of aligned characters even with variation in pitch p ofAp, the pitch interval t of the synchronizing pulse signal 13 must be changed in accordance with the following equa- In other words, the misalignment of printed characters can be avoided by employing the pulse interval t in place of t. In the present method, the time interval t can readily be changed to t simply by sliding the pickup head provided for generating the synchronizing pulse signal in parallel with the axis of the pattern cylinder 4 so as to completely compensate for. the inaccuracy of the pitch p of the type rows on the rotary electrode 1, and thus, it is at all times possible to realize an accurate line-printing operation. Similarly, in the event that the value of speed v be. disturbed, for example, by a few percent, it is possible to obtain printed lines of aligned characters by changing pulse interval from value 1 to a value corresponding to t multiplied by a value inversely proportional to the variation in the value of (V-v) thereby to satisfy the Equation 1.

Moreover, with the previously proposed system, it has been extremely difiicult to vary the pitch L of printed lines since strict numerical relationships must exist among On the other hand, in the present method, which employs pattern cylinder 4 directly coupled with the type-carrying electrode 2 for obtaining a synchronizing pulse signal 13' and a start signal 14, the pitch L of printedlines can be varied with extreme ease within a predetermined range simply by adjusting the position of the pickup head 7-8 to satisfy the Equation 1, after varying the ratio C of the speed .of types 2 to that of recording sheet 17 in such a manner as to satisfy the condition (3) with approximation of a few percent.

Though not illustrated, the present method employs, in addition to the type-carrying electrode 1 integrally coupled with the pattern cylinder 4, a drive mechanism arranged so that the ratio C of the'speed of types 2 to that of recording sheet 17 remains constant even if the driving speeds be varied widely and the line pitch condition is thus satisfied at all times irrespective of the speed of the drive source.

Having described an electrostatic line-printing system embodying the present invention, it is to be understood that the invention can also be applied to a system employing electromagnetic printing hammers and that a suitable pattern disc may be substituted for the pattern cylinder described as means for producing synchronizing pulses. In this latter case, the synchronizing pattern apparently includes curved stripes. obtained by replacing the optical or photoelectric device by a magnetic device including a magnetic pattern and an electromagnetic pickup for deriving a synchronizing pulse signal therefrom, or also by an electric device including an array of electroconductive segments and a 00- operating electric brush means.

Also, the same result may be As apparent for the foregoing, the present invention has a number of important advantages over the previous line-printing system. Among others, the present invention provides means for compensating for various unavoidable inaccuracies in the arrangement and dimensions of parts as well as for disturbances possibly occurring in operation and thus makes it possible at all times to satisfy the conditions for accurate line-printing operation. It will also be appreciated that the present invention eliminates any complicated and expensive parts requiring high-precision machining and any precise but less dependable speed-regulating mechanisms and oscillator circuits, and thus drastically reduces the cost of the entire system while increasing its reliability and service life.

What is claimed is:

1. A line printing apparatus for printing the information signal output of an electronic computer or the like, comprising:

means for driving said rotary type-carrying member at a linear speed V such that C g=constant and selective control circuit means operatively connected with said printing heads and including means for selectively operating said printing heads in response to said information signal output and said synchronizing pulse to effect on said sheet a lineprinting in a variable pitch line.

2. A line printing apparatus for printing the information signal output of an electronic computer or the like, comprising:

a plurality of relatively stationary selective printing heads;

a rotary type-carrying member having at least one set of m kinds of types arranged in m rows and n columns, each row including n types of the same character;

synchronizing means for producing a plurality of synchronizing pulses all having the same pulse interval t including a rotary element having means for varying by the same amount the pulse interval t for all the synchroniizng pulses, and connecting means operatively connecting said rotary element with i said rotary type carrying member;

means for feeding a recording sheet between said printing heads and said rotary type carrying member at a travelling speed v;

means for driving said rotary type-carrying member at a linear speed V such that C constant where p is the dimension of the printing head taken in the same direction as a, and L is the pitch of the printed lines.

3. A line printing apparatus for printing the information signal output of an electronic computer or the like, comprising:

heads;

a rotary type-carrying member;

synchronizing means for producing a plurality of synchronizing pulses all having the same pulse interval t including a rotary drum-type element having means along the periphery of the drum for varying by the same amount the pulse interval t for all the synchronizing pulses, and connecting means operatively connecting said rotary element with said rotary type carrying member;

means for feeding a recording sheet between said printing heads and said rotary type carrying member at a travelling speed v;

means for driving said rotary type-carrying member at a linear speed V such that a plurality of relatively stationary selective printing C =g= constant and selective control circuit means operatively connected with said printing heads and including means for selectively operating said printing heads in response to said information signal output and said synchronizing pulse to eflect on said sheet a lineprinting in a variable pitch line.

4. A line printing apparatus for printing the information signal output of an electronic computer or the like, comprising:

a plurality of relatively stationary selective printing heads;

a rotary type-carrying member having at least one set of m kinds of types arranged in in rows and n columns, each row including n types of the same character;

synchronizing means for producing a plurality of synchronizing pulses all having the same pulse interval t including a rotary drum-type element having means along the periphery of the drum for varying by the same amount the pulse interval t for all the synchronizing pulses, and connecting means operatively connecting said rotary element with said rotary type carrying member;

means for feeding a recording sheet between said printing'heads and said rotary type carrying member at a travelling speed '11;

means for driving said rotary type-carrying member at a linear speed V such that C constant and selective control means operatively connected with set being I in the circumferential direction, and the various parameters being so chosen as to substantially satisfy the condition p p' a+ (m1)vt 8. Where p is the" dimension of the'printing head taken in the same direction as a, and L is the pitch of the printed lines.

5. A line printing apparatus according tov claim 4, wherein said synchronizing means includes pick-up means for picking up the synchronizing pulses produced by said rotary drum-type element, and means for selectively moving said pick-up means relative to said rotary drum-type element in the axial direction of the latter.

6. A line printing apparatus according to claim 5, wherein said means along the periphery of the drum are constituted by m surface portions whose range of pitch variation is v p p where p p p as expressed in radians.

References Cited by the Examiner UNITED STATES PATENTS 2,514,433 7/50 Wilbur 250-233 X 2,757,605 8/56 Dumey. 2,985,872 5/61 Beltrami.

WILLIAM B. PENN, Primary Examiner. 

1. A LINE PRINTING APPARATUS FOR PRINTING THE INFORMATION SIGNAL OUTPUT OF AN ELECTRONIC COMPUTER OR THE LIKE, COMPRISING: A PLURALITY OF RELATIVELY STATIONARY SELECTIVE PRINTING HEADS; A ROTARY TYPE-CARRYING MEMBER; SYNCHRONIZING MEANS FOR PRODUCING A PLURALITY OF SYNCHRONIZING PULSES ALL HAVING THE SAME PULSE INTERVAL T INCLUDING A ROTARY ELEMENT HAVING MEANS FOR VARYING BY THE SAME AMOUNT THE PULSE INTERVAL T FOR ALL THE SYNCHRONIZING PULSES, AND CONNECTING MEANS OPERATIVELY CONNECTING SAID ROTARY ELEMENT WITH SAID ROTARY TYPE CARRYING MEMBER; MEANS FOR FEEDING A RECORDING SHEET BETWEEN SAID PRINTING HEADS AND SAID ROTARY TYPE CARRYING MEMBER AT A TRAVELLING SPEED V; MEANS FOR DRIVING SAID ROTARY TYPE-CARRYING MEMBER AT A LINEAR SPEED V SUCH THAT 